Method and device for generatively manufacturing a three-dimensional object with three-dimensional coded character

ABSTRACT

The present invention relates to a method and to a device for generatively manufacturing a three-dimensional object ( 3 ). A powdery material ( 11 ) is applied layerwise onto a support ( 5 ) of the device or onto a previously applied layer, and the powdery material ( 11 ) is solidified by energetic radiation ( 8′ ) at locations corresponding to the object ( 3 ). The powdery material ( 11 ) is solidified such that a digital, machine readable and three-dimensional coded character is provided at a surface of the object ( 3 ).

The present invention relates to a method and to a device formanufacturing a three-dimensional object.

WO 2005/099635 A1 describes a method of manufacturing athree-dimensional object which contains inside an identifiablestructure. The identifiable structure consists of a contrast agent andcan be viewed by X-rays, for example. U.S. Pat. No. 6,939,501 B2describes a semiconductor device, onto which a sequence of letters ornumbers is set by means of stereolithography. WO 02/24127 A2 describes amethod of manufacturing an otoplastic, in particularly an in-ear hearingdevice, for example by laser-sintering, wherein the otoplastic comprisesnotches and/or bulges at the surface. The notches and/or bulges define amachine readable marking of the otoplastic. The notches and/or bulgesare usually two-dimensional coded because they bear information which isdefined by the length and depth of the notches and/or bulges.

In laser-sintering, the manufactured objects must usually be marked forquality control. Up to now, this has been made by a writing (label)consisting of a sequence of letters or numbers which are sintered on orinto the object. The writing shall be created by the laser-sinteringdevice directly at the objects, because later allocation of theinformation to the objects is hardly possible when many objects (forexample some hundreds) are manufactured in one job and the objects arethen withdrawn from the laser-sintering device. Then, the objects cannotunambiguously be allocated to the job and to the previous positionwithin the building space anymore. A further problem is caused for smallobjects which offer only a small space for the writing. Due to theprocess, the writing can also be provided only with a predeterminedwidth, height and resolution.

It is the object of the present invention to provide a method and adevice for manufacturing a three-dimensional object, which are capableto mark the object with much information as possible.

This object is achieved by the method of manufacturing athree-dimensional object having the features of claim 1 and by thedevice for manufacturing a three-dimensional object having the featuresof claim 11.

Advantageously, back tracking (tracking) of the object is possible bythe marking. Advantageous further developments are subject of thedependent claims.

Further aims and purposes of the invention can be gathered from thedescription of embodiments on the basis of the enclosed drawings. In thedrawings show:

FIG. 1 a schematic view of a device for manufacturing athree-dimensional object according to the present invention;

FIG. 2 a top view of a three-dimensional coded character according to afirst embodiment of the present invention;

FIG. 3 a cross-sectional view of the three-dimensional coded characteraccording to the first embodiment of the present invention;

FIG. 4 a cross-sectional view of a three-dimensional coded characteraccording to a second embodiment of the present invention; and

FIG. 5 a cross-sectional view of a three-dimensional coded characteraccording to a third embodiment of the present invention.

FIG. 1 shows a schematic view of a device for manufacturing athree-dimensional object 3 according to the present invention, which isformed as laser-sintering device in the embodiment.

The laser-sintering device comprises a frame 1 which opens at the topand comprises therein a platform 5, which is movable in the verticaldirection and supports the three-dimensional object 3 to bemanufactured. The frame 1 and the platform 5 define therein a buildingspace. The platform 5 is connected to a lift mechanics 4, by which it ismoved in the vertical direction such that the layer of the object 3,which should be solidified, lies within a working plane.

Further, an applicator 10 for applying a layer of a powdery material 11is provided. As powdery material 11, all laser-sintering powders can beused such as laser-sinterable plastics like polyamide, polystyrene, andin particular high-temperature plastics like PEEK, metals, ceramics,moulding sand and compound materials. As metal containing powderymaterial, any metals and alloys thereof as well as mixtures of metalliccomponents or non-metallic components come into question. First, thepowdery material 11 is supplied to the frame 1 from a storage containerof the applicator 10. Thereafter, the applicator 10 is moved to apredetermined height above the upper periphery 2 of the frame 1 withinthe working plane 6 so that the layer of the powdery material 11 lies ina defined height above the lastly solidified layer. Further, the devicecomprises a laser 7 which generates a laser beam 8, 8′ which is focussedto arbitrary points in the working plane 6 by deflection means 9.Thereby, the laser beam 8, 8′ can selectively solidify the powderymaterial 11 at the locations corresponding to the cross-section of theobject 3 to be manufactured.

Reference sign 100 designates a process chamber, in which the frame 1,the platform 5, the lift mechanics 4 and the applicator 10 can bearranged. The process chamber 100 has in the upper area an opening forintroducing the laser beam 8, 8′. Preferably, an inert gas is introducedinto the process chamber 100. Further, a control unit 40 is provided, bywhich the device is controlled in a coordinated manner so as to executethe building process.

During operation of the device, the platform 5 is lowered by the liftmechanics 4 in a first step, until the upper side thereof lies below theworking plane 6 by the thickness of one layer. Then, a first layer ofthe powdery material 11 is applied and smoothened on the platform 5 bythe applicator 10. Thereupon, the control unit 40 controls thedeflection means 9 such that the deflected laser beam 8, 8′ selectivelyimpinges at those locations of the layer of the powdery material 11,which shall be solidified. Thereby, the powdery material 11 issolidified and/or sintered at these locations, so that thethree-dimensional object 3 is created here.

In a next step, the platform 5 is lowered by the lift mechanics 4 by thethickness of the next layer. A second layer of powdery material isapplied, smoothened by the applicator 10 and selectively solidified bymeans of the laser beam 8, 8′. These steps are repeated until thedesired object 3 is manufactured.

The three-dimensional objects 3 have a digital, machine readable andthree-dimensional coded character 12 according to the present invention.The character 12 contains information such as a time stamp, the positionof the object 3 within the device, the job number, the material of theobject 3, etc. Such information can be used for quality control. FIG. 2shows a top view of the three-dimensional codes character 12 accordingto a first embodiment of the present invention, and FIG. 3 shows across-sectional view of the three-dimensional coded character 12according to the first embodiment.

In the first embodiment, the character 12 defines in a surface 13 of thethree-dimensional object 3 a two-dimensional matrix 12, wherein thematrix 12 comprises a given number of components 14, 15. Preferably, thematrix 12 is larger than a 2×2-matrix, and in the first embodimentaccording to FIG. 2, the matrix 12 is a 8×8-matrix. For example, therespective components 14, 15 of the matrix 12 as shown in FIG. 2 may bequadrates with an edge length of 0.8 mm. Advantageously, the computingpower of the control unit 40 for manufacturing the matrix 12 isrelatively small and constant, when this is compared with the computingpower for a character string of letters and numbers.

The components 14, 15 of the matrix 12 have different distances (heightsor depths) from the surface 13 of the object 3. FIG. 3 shows that thematrix 12 comprises first components 14 having a first distance from thesurface 13 of the object 3, and second components 15 having a seconddistance from the surface 13. In the first embodiment, the firstcomponents 14 as well as the second components 15 of the matrix 12 formdepressions in the surface 13 of the object 3. However, the firstcomponents 14 of the matrix 12 have a smaller distance from the surface13 than the second components 15 of the matrix 12.

FIG. 4 shows a cross-sectional view of the three-dimensional codedcharacter 12′ according to a second embodiment of the present invention,wherein the first component 14′ as well as the second component 15′ ofthe matrix 12′ form embossments from the surface 13 of the object 3.However, the first components 14′ of the matrix 12′ have a largerdistance from the surface of the object 3 than the second components 15′of the matrix 12′.

FIG. 5 shows a cross-sectional view of a three-dimensional codedcharacter 12″ according to a third embodiment of the present invention,wherein the first components 14″ are substantially aligned to be flushwith the surface 13 of the object 3, and the second components 15″ aredepressed in the surface 13. In a modification of the third embodiment,the second components 15″ may be embossed from the surface 13, while thefirst components 14″ are substantially aligned to be flush with thesurface 13.

According to the present invention, the three-dimensional coded signs12; 12′; 12″ are digital and machine readable. For example, an embossedand/or higher component 14; 14′; 14″ of the matrix 12; 12′; 12″ mayrepresent the binary 1, while a depressed and/or lower component 15;15′; 15″ of the matrix 12; 12′; 12″ represents the binary 0, or viceversa. The 8×8-matrix 12 as shown in FIG. 2 therefore defines a word of64 bit.

Reading the character 12; 12′; 12″ is performed by machine, for exampleby pin scanning, laser scanning or by means of a CCD-camera havingdownstream a pattern recognition. In order to easily read the character12; 12′; 12″, the first components 14; 14′; 14″ of the matrix 12; 12′;12″ preferably have another surface property than the second components15; 15′; 15″ of the matrix 12; 12′; 12″. In particular, the surfaceproperty may be a surface roughness or a reflection coefficient.

A further embodiment may comprise a step of tinting a part of thecomponents. For example, this can be made in the second embodiment ofFIG. 4 by pressing the character 12′ against an ink pad which issaturated with paint or ink. Thereby, only the first components 14′ aretinted.

In the third embodiment of FIG. 5, a paint or a finish can be applied onthe character 12″, and in a subsequent step, the character 12″ is wipedoff by a wiper so that the colour or the finish only remains on thedepressed second components 15″ of the matrix 12″.

The scope of protection is not restricted to the representedembodiments, but it also includes further changes and modifications,provided that they fall within the scope as defined by the enclosedclaims.

The method according to the present invention is not only applicable tolaser-sintering, but also to all generative methods based on powder,where a single material and/or a single powdery material is used in oneapplied layer which is solidified by the energetic beam. If necessary,the single material and/or the single powdery material is added by anactivator. The energetic beam must not necessarily be a laser beam, butit can also be an electron beam, for example.

The structure of the digital, machine readable and three-dimensionalcoded character 12 is not restricted to the shape of a matrix. Instead,an arbitrary 3D code can be used.

1. Method of generatively manufacturing a three-dimensional object bymeans of a device, comprising the following steps: layerwise applying apowdery material onto a support of the device or a previously appliedlayer; solidifying the powdery material by energetic radiation atlocations corresponding to the object, wherein the powdery material issolidified such that a digital, machine readable and three-dimensionalcoded character is provided at a surface of the object.
 2. Methodaccording to claim 1, wherein the character defines a two-dimensionalmatrix in the surface of the three-dimensional object, wherein thematrix has a plurality of components having different distances from thesurface of the object.
 3. Method according to claim 2, wherein thematrix comprises a first component having a first distance from thesurface of the object and a second component having a second distancefrom the surface of the object.
 4. Method according to claim 3, whereinthe first component is substantially aligned to be flush with thesurface of the object, and the second component is embossed from thesurface of the object or depressed in the surface.
 5. Method accordingto claim 2, wherein the first components of the matrix comprise adifferent surface property from the second components of the matrix. 6.Method according claim 2, further comprising a step of applying a paintor a finish on those components which have a certain distance from thesurface of the object.
 7. Method according to claim 2, wherein thematrix is surrounded by a frame which has a different height or adifferent surface property from the surface of the object.
 8. Methodaccording to claim 1, wherein only a single powdery material, which is,if necessary, provided with an activator, is used for one layer. 9.Method according to claims 2, wherein a component of the matrix bearsbinary information.
 10. Laser-sintering method as the method accordingto claim
 1. 11. Device which performs the method according to claim 1.